{
\def\sym#1{\ifmmode^{#1}\else\(^{#1}\)\fi}
\begin{tabular}{l*{3}{ccccc}}
\hline\hline
                    &\multicolumn{2}{c}{(1)}  &\multicolumn{2}{c}{(2)}  &\multicolumn{3}{c}{(3)}                        \\
                    &\multicolumn{2}{c}{}     &\multicolumn{2}{c}{}     &\multicolumn{3}{c}{}                           \\
                    &        mean&          sd&        mean&          sd&           b         &           t&           p\\
\hline
attrition           &       0.030&       0.170&       0.042&       0.200&      -0.012         &    (-1.247)&     (0.212)\\
\hline
Observations        &         707&            &         793&            &        1500         &            &            \\
\hline\hline
\end{tabular}
}
